It is desirable to have a convenient method and apparatus for testing chicken eggs to determine their freshness and suitability for human consumption. More particularly, it is desirable to have such a method and apparatus that can be conveniently used in a typical household kitchen.
Unfertilized chicken eggs have a typical useful life of about 31 days, if they are transported and stored in an appropriate environment. Many factors, including storage temperature and humidity, will affect the length of time that eggs can be maintained in a condition suitable for human consumption.
For eggs purchased from reliable grocers, date codes on the egg cartons can be relied upon to some extent for determining how old and fresh the eggs in the carton are likely to be, but this method is not infallible due to the many factors which can influence freshness and shelf life as the eggs make their way from the henhouse to the refrigerator shelf. Eggs from Free-Range chickens are particularly troublesome in this regard, because the eggs may not be gathered as quickly as commercial laying house eggs, given that the chickens may lay them in a place where they will not be immediately discovered.
It is known that as eggs age, they lose moisture through the shell, and a small air pocket inside the shell gets larger. It is also known that the freshness of a chicken egg may be tested by placing the egg in a vessel containing cool fresh water, and observing whether the egg floats, completely or partially in the water.
Specifically, it is known that a fresh egg will lie on its side on the bottom of the vessel. A slightly older egg will still lie generally on the bottom, but the larger end of the egg may float slightly off the bottom. As the egg continues to age, it will stand in the water with its small end touching the bottom. At a few more days of age, the egg will begin to bob up off of the bottom and float part way up in the water. A really old egg will float high in the water, perhaps even on the surface of the water.
For direct consumption, eggs which lie on the bottom are the freshest and most desirable. Eggs which are somewhat less fresh may still be quite good for direct consumption. Eggs which are less fresh yet may still be used for baking and in other indirectly consumed food products. Floating eggs should not be used for human consumption.
Although the above stated information regarding testing of eggs for freshness in water has been known for many years, the method is imprecise and prone to mistakes in interpretation. What is needed is an improved method and apparatus for more precisely determining the freshness of chicken eggs and their suitability for human consumption, in a manner that can be utilized in a typical household kitchen